Microbial activity around the Connecting Gallery

Within the frame of HLW disposal Boom Clay is studied as the reference host rock. In order to study Boom Clay an underground laboratory was constructed but due to the excavation the clay was perturbed and these perturbations appear to be accompanied by microbial activity. From a corrosion perspective activity of sulphate reducing bacteria (SRB) is of major importance since these bacteria have a major influence on the sulphur species and thus affect the corrosion studies. This report aims to investigate the abundance of SRB coupled with variations in chemical composition of the clay water as a function of distance to the gallery. Since SRB activity in Boom Clay is triggered by the excavation/exploitation of an underground repository via the oxidation of pyrite, it's not unlikely that differences in the SRB population as a function of distance to the gallery exist. A second goal is to start work on the identification of the main species of SRB that are present in Boom Clay. The knowledge of how much and which SRB are present in Boom Clay is a necessary first step in the estimation of the possible influence of SRB on the supercontainer design.